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Cut Parallel (cut + parallel)
Selected AbstractsA laboratory study of seismic velocity and attenuation anisotropy in near-surface sedimentary rocksGEOPHYSICAL PROSPECTING, Issue 5 2007Angus I. Best ABSTRACT The laboratory ultrasonic pulse-echo method was used to collect accurate P- and S-wave velocity (±0.3%) and attenuation (±10%) data at differential pressures of 5,50 MPa on water-saturated core samples of sandstone, limestone and siltstone that were cut parallel and perpendicular to the vertical borehole axis. The results, when expressed in terms of the P- and S-wave velocity and attenuation anisotropy parameters for weakly transversely isotropic media (,, ,, ,Q, ,Q) show complex variations with pressure and lithology. In general, attenuation anisotropy is stronger and more sensitive to pressure changes than velocity anisotropy, regardless of lithology. Anisotropy is greatest (over 20% for velocity, over 70% for attenuation) in rocks with visible clay/organic matter laminations in hand specimens. Pressure sensitivities are attributed to the opening of microcracks with decreasing pressure. Changes in magnitude of velocity and attenuation anisotropy with effective pressure show similar trends, although they can show different signs (positive or negative values of ,, ,Q, ,, ,Q). We conclude that attenuation anisotropy in particular could prove useful to seismic monitoring of reservoir pressure changes if frequency-dependent effects can be quantified and modelled. [source] Measurement of lesion area and volume by three-dimensional spoiled gradient-echo MR imaging in osteonecrosis of the femoral headJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2003Yuki Kishida Abstract The purpose of this investigation is to evaluate the diagnostic ability of three-dimensional spoiled gradient-echo (3D SPGR) magnetic resonance (MR) imaging in cases of osteonecrosis of the femoral head (ONFH), and to determine the accuracy of 3D SPGR imaging in area and volume measurement of ONFH. T1-weighted spin-echo (SE) and 3D SPGR imaging were performed on 20 femoral heads obtained from patients with ONFH. After MR imaging, the femoral heads were cut parallel to the imaging plane and were evaluated histologically. Areas and volumes of necrotic lesions were measured with a computer program and the deviation between MR images and anatomical measurements was evaluated. A low signal intensity band on 3D SPGR MR images was observed in all femoral heads and corresponded histologically to repaired marrow with viable fibrous mesenchymal tissue. The area proximate to the low band area coincided with the necrotic region. Both area and volume measurements by T1-weighted SE and 3D SPGR images showed a strong correlation to histological measurements. The discrepancies between histological and imaging results were minimal in 3D SPGR imaging, especially at the anterior and posterior portions of the femoral head. Three-dimensional SPGR imaging provides more accurate measurements of the area and volume of a necrotic lesion than T1-weighted SE imaging. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Nitric oxide mediates the inhibitory effect of ethanol on the motility of isolated longitudinal muscle of proximal colon in ratsNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2007S. L. Wang Abstract, The aim of the present study was to investigate the effect of ethanol on colon motility in rats and to test the possibility that nitric oxide (NO) mediates this effect. Proximal colon longitudinal muscle strips (LM) (8 × 3 mm) cut parallel to the longitudinal muscle fibres of the colon were isolated and mounted in an organ bath. Ethanol (0.57, 0.87 and 1.30 mmol L,1) dose-dependently inhibited the motility of LM. Longitudinal muscle strips from female rats were more sensitive to the inhibitory effect of ethanol than that from male rats. L-NAME (N -nitro- l -arginine methyl ester) (100 ,mol L,1), AG (aminoguanidine) (10 ,mol L,1), ODQ (1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one) (10 ,mol L,1) and PTIO (2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide) (200 ,mol L,1) partly blocked the inhibitory effect of ethanol on LM. Pretreatment with L-NAME, AG, ODQ and PTIO abolished the sex difference of the inhibitory effect of ethanol on LM. Tetrodotoxin (TTX) (10 ,mol L,1) partly blocked the inhibitory effect but did not influence the sex difference. The relaxation of LM induced by SNP (sodium nitroprusside) (0.1,10 ,mol L,1) in female rats was greater than that in male rats. In conclusion, ethanol inhibited the colon motility in vitro. This inhibitory effect on LM was mediated by NO through the iNOS , NO , cGMP pathway. [source] Additional reverse transcription,polymerase chain reaction of peripheral slices is not superior to analysis of the central slice in sentinel lymph nodes from melanoma patientsBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2004H-J. Blaheta Summary Background The status of the sentinel lymph node (SLN) is an important prognostic factor in patients with cutaneous melanoma. Reverse transcription,polymerase chain reaction (RT,PCR) has been used as a sensitive means of detecting tumour cells in SLNs. Objectives To determine whether RT,PCR analysis of the SLN using both the central and the peripheral slices is more sensitive than molecular analysis of the central slice only. Methods Eighty-three SLNs from 59 patients with primary cutaneous melanoma were identified by SLN mapping. All SLNs were bisected along their longitudinal axis to produce two equal halves. One half was used for histology and immunohistochemistry, and the other was analysed by RT,PCR for tyrosinase and MelanA. Parallel to the longitudinal axis, one central slice (approximately 2 mm in thickness) was cut manually. This central slice was used for our standard RT,PCR protocol. In the current study, up to eight additional peripheral slices (each approximately 2 mm in thickness) were cut parallel to the existing cut surface. These peripheral slices were analysed by additional RT,PCR. Results Standard RT,PCR of the central slice yielded positive results in 34 of 59 patients (57%). Additional RT,PCR of peripheral slices demonstrated positive findings in six additional patients (10%) who were initially negative by standard RT,PCR of the central slice. In detail, seven of those 34 patients positive by standard RT,PCR of the central slice had positive histological findings. In each of these seven patients, RT,PCR was positive both in the central slice as well as in the peripheral slices. The remaining 27 patients with positive RT,PCR results of the central slice showed negative histological findings. Only nine (33%) of these 27 patients had a positive RT,PCR also in the peripheral slices. Finally, all 25 patients with negative RT,PCR results in the central slice showed negative histological findings. Six of these patients (24%) revealed positive RT,PCR results on the analysis of peripheral slices. However, three of these patients expressed only MelanA but not tyrosinase. Thirty lymph nodes from 24 nonmelanoma patients served as negative controls for RT,PCR. In three of these 24 patients (13%) expression of MelanA but not tyrosinase was detected by RT,PCR. Conclusions Molecular analysis of peripheral slices yielded six additional patients (10%) positive by RT,PCR who were initially negative by standard RT,PCR of the central slice. However, three of these six patients were found to express only MelanA but not tyrosinase. As MelanA expression was also found in 13% of control lymph nodes, positive MelanA expression alone in SLNs of melanoma patients requires cautious interpretation in order to avoid false-positive findings. Thus, additional molecular processing of peripheral slices did not significantly increase the number of patients with RT,PCR-positive SLNs. [source] | ||||||||||